Lecture 3

Question 1

propulsive movement

Answer 1

push contents forward through the digestive tract

Question 2

mixing movement

Answer 2

promote breakdown and facilitate absorption across the digestive wall

Question 3

mechanical digestion

Answer 3

physical mixing and churning that breakdown large masses of food into smaller masses of food

Question 4

chemical digestion

Answer 4

using enzymes to break bonds of large molecules into small molecules

Question 5

why is it important to break down food physically

Answer 5

to increase surface area for enzyme action

Question 6

main enzyme in saliva

Answer 6

amylase (alpha 1-4 bonds in starch)

Question 7

other components of saliva

Answer 7

electrolytes, lingual lipase

Question 8

purpose of mucus

Answer 8

lubrication
protect gut wall from digestive enzymes

Question 9

order of layers

Answer 9

1. lumen
2. mucosa
3. muscularis externa
4. serosa

Question 10

mucosa

Answer 10

innermost mucous membrane layer
produces and releases secretions needed for digestion
lymphoid tissues protect the body

Question 11

submucosa

Answer 11

connective tissue w/blood vessels, lymphatic vessels, nerves, and lymphoid tissue

Question 12

muscularis externa

Answer 12

two layers of smooth muscles
- longitudinal and circular
- responsible for GI motility

Question 13

serosa

Answer 13

connective tissue
outer cover that protects the GI tract

Question 14

bolus components

Answer 14

food and saliva

Question 15

_____ grinds and mixes food w/gastric juice to form _____

Answer 15

antrum, chyme

Question 16

how does volume affect motility of the stomach

Answer 16

when full, motility and emptying is stimulated

Question 17

fluidity affect motility of stomach

Answer 17

when more broken down, chyme is easier to move, and emptying will be stimulated

Question 18

how do high levels of fat, acid, distension of small intestine affect motility of the stomach

Answer 18

inhibits emptying until the small intestine can process more

Question 19

how does stress impact motility of the stomach

Answer 19

inhibits motility and emptying via sympathetic nervous system

Question 20

cardia

Answer 20

• part near esophagus
• contains cardiac glands

Question 21

pylorus

Answer 21

• part priximal to pyloric sphicter
• contains pyloric glands

Question 22

fundus/body

Answer 22

• between cardia and pylorus
• contains fundic/gastric glands

Question 23

cardiac glands

Answer 23

• mainly mucus cells
• some entereoendocrine cells interspersed

Question 24

pyloric glands

Answer 24

• mucus cells
• entereoendocrine cells (g and d cells)

Question 25

gastric glands

Answer 25

• parietal cells
• chief cells
• mucus cells
• entereoendocrine cells (g cells)

Question 26

parietal cells

Answer 26

• gastric acid (HCl)
• intrinstic factor (Ca+++ absorption)

Question 27

enterochromaffin like cell

Answer 27

• histamine (stimulates acid)

Question 28

chief cells

Answer 28

• pepsin (ogen)
• gastric lipase

Question 29

D cells

Answer 29

• somatostatin (inhibits acid)

Question 30

G cells

Answer 30

gastrin ( stimulates acid)

Question 31

gastric juice

Answer 31

• Hcl
• pepsinogen (inactive precursor of pepsin)
• Intrinsic factor
• gastrin
• lipase
• amylase

Question 32

HCl functions

Answer 32

1. converting pepsinogen to pepsin
   denaturing proteins
   killing bacteria ingested with food
   releasing nutrients from organic complexes

Question 33

main proteolytic enzyme in the stomach

Answer 33

pepsin

Question 34

absorption in the stomach

Answer 34

limited

Question 35

what causes the breakdown of vitamin b12 bound to food

Answer 35

acidic environment of the stomach

Question 36

percentage of oxygen molecules at any iven altitude

Answer 36

21%

Question 37

saliva compoentns

Answer 37

water (99.5%)
salivary amylase
electrolytes
lingual lipase

Question 38

gastro-esophageal sphincter

Answer 38

connects esophagus and stomach

Question 39

pyloric sphincter

Answer 39

connects stomach to duodenum